Luciferases have become invaluable detection tools in molecular biology and other fields. Their utility is imited by their physical liability. The currently available luciferases are sensitive to extremes of temperature and pH, which precludes their use as detectors in applications such as the polymerase chain reaction. Recently, a luciferase from the jellyfish Periphylla was described which is active from pH 1 to 11, and resists denaturation by boiling and chaotropic agents. Further, this luciferase has the highest quantum yield of any known luciferase. Our goals are to purify, clone and express this extremely robust and bright luciferase. This luciferase "beacon" can then be coupled to other detector molecules, including proteins and nucleic acids, and used in a wide variety of detection schemes involving extreme conditions.